A. Field of the Invention
This invention relates to dilators for use in penile implant and other urologic surgery.
B. Prior Art Background
In penile implant surgery, the need to dilate the corpora cavernosa to receive an inflatable or other type of prosthetic implant has been long known. The purpose of the implant is to enable the patient to achieve penile erection after the patient has lost this ability through disease or otherwise. In the process of the surgical technique to implant the prosthesis, the corpora cavernosa must be opened, dilated, and the prosthetic device inserted in the corpora. Since the penis is flaccid during the operation, a needle and suture must be taken through the corpora and exit through the glans end of the corpora and through the glans in order to pull the generally cylindrical implant through the length of the corpora.
Prior art devices which have been developed to accomplish this technique include the device of Furlow. This device is used for carrying needle and suture to the glans through the corpora after a series of generally cylindrical dilators, which, in order of increasing size, are inserted and removed so that the next larger cylinder may be inserted. The corpora, or other such opening is thereby dilated by the insertion of each successively larger dilating cylinder. This technique has the severe disadvantage of abrading the interior tissues since dilation depends on squeezing successively larger rods into the opening and along the corpora. Because the corpora is spongy tissue, there is no assurance that the same passage would be opened each time a new dilating rod is inserted. False passages can be created, with additional trauma resulting.
Another device is the device of Kollman. This dilator includes a longitudinally split dilating shaft, the sections of which are separated by a screw-powered lever at the base of the sections. Because of the resistence which is exerted by the glans end of the corpora on the tips of the sections, such devices have been difficult to use with precision and are usually ineffective in fully dilating the glans end of the corpora.
Neither of the aforementioned prior art devices include the means for dilation and for delivering accurately to and through the glans a needle and suture. The inaccuracy of needle placement through the glans of a flaccid penis, which is often the case with use of the Furlow device, has caused the needle to exit the side of the penis, or off center of the glans and can enter the urethra, causing unnecessary tissue damage. Additionally, when the needle is carried to the glans end of the corpora by Furlow's device, the needle rests loosely in a slot in the end of the largest cylindrical dilator to be used. If the needle is not to be passed through the glans before withdrawing the device, the needle can slip out and be lost in the corpora as the device is withdrawn.
C. Summary of the Invention
The invention includes a unitary variable dilator with longitudinally split sections radially separable from each other and a tapered or wedge-shaped inner member for positively and accurately separating the sections with means for securely holding an instrument at the point end of the inner member. The dilator is expanded radially by inserting the wedge-shaped inner member between the sections. A minimum of abrasion of the interior of the corpora is caused by this dilator because there is no multiple inserting and removing of different size dilators of the prior art. Another advantage of the present invention is the high degree of stability in positioning of the glans and accurate penetration thereof by the needle and suture in order to pull the implant therethrough. The inner sides of the dilator have cooperating grooves or slots along their length designed to receive the inner member as it is slid along the predetermined path between the split dilator sections to achieve radial expansion.
One embodiment of the invention includes markings indicating depth of penetration along the side of the dilator and markings along the inner member to indicate degree of dilation and position within the corpora of the instrument held by the inner member.